Hello kbaglio, Unfortunately you've got malware ..... Please see : https://malwarefixes.com/remove-search-dolanbaross-com-mac/ As you've already mentioned that you don't see anything unfamiliar in Add-ons => Plugins, I can skip asking you to check there. Would you go over this article and run every malware scan that is listed in the article - what one doesn't pick up, the other one will : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Especially for Mac : https://www.malwarebytes.com/mac/ I hope that helps ......